Deuteronomy 4:11

And ye came near and stood under the mountain At the foot of it, in the lower part of the mountain, as the Targum of Jonathan, and agrees with ( Exodus 19:17 )

and the mountain burnt with fire unto the midst of heaven; the flame and smoke went up into the middle of the air: with darkness, clouds, and thick darkness; which thick darkness was occasioned partly by the smoke, which went up like the smoke of a furnace, and partly by the thick clouds, which were on the mount, and covered the face of the heavens, which were black and tempestuous with them; the Septuagint renders it a "tempest", ( Exodus 19:18 ) ( Hebrews 12:18 ) , which denotes the obscurity of the law, and the terrors it works in the minds of men.